[jira] [Created] (COMPRESS-221) Compress cannot run without XZ included

["Matt Quigley (JIRA)" <ji...@apache.org>]

Matt Quigley created COMPRESS-221:
-------------------------------------

             Summary: Compress cannot run without XZ included
                 Key: COMPRESS-221
                 URL: https://issues.apache.org/jira/browse/COMPRESS-221
             Project: Commons Compress
          Issue Type: Bug
    Affects Versions: 1.4.1
            Reporter: Matt Quigley


In previous versions of Compress, we used the Compress library in our application without requiring any other libraries.  Since the introduction of XZ, the library crashes because it does not dynamically try to find the XZ classes. Our application does not use or need XZ, and we _cannot_ add another ~100KB file to our application.

To reproduce:

{code}
        try {
// <properties><mimeTypeRepository resource="/etc/tika-mimetypes.xml" magic="true"/></properties>
            tika = new TikaConfig(getClass().getClassLoader().getResourceAsStream("etc/tika-config.xml"));
        } catch (Throwable t) {
            t.printStackTrace();
            throw new MimeTypeException("Cannot load tika-config.xml", t);
        }
        detector = tika.getDetector();
        MediaType contentType = MediaType.OCTET_STREAM;
        contentType = detector.detect(tika, metadata); // error here
{code}

Calling {{Detector.detect(InputStream, Metadata)}} causes a {{NoClassDefFoundError}} because it is trying to find the XZ files using a direct reference to the XZ classes.  {{Detector.detect:61}} uses {{ZipContainerDetector.detect}} to use {{CompressorInputStream createCompressorInputStream(InputStream)}}.

The problem in {{public CompressorInputStream createCompressorInputStream(InputStream)}} is it directly calls static methods on the {{XZCompressorInputStream}} class which aren't in the classpath.

{code}
      if (BZip2CompressorInputStream.matches(signature, signatureLength)) {
        return new BZip2CompressorInputStream(in);
      }
      if (GzipCompressorInputStream.matches(signature, signatureLength)) {
        return new GzipCompressorInputStream(in);
      }
      if (XZCompressorInputStream.matches(signature, signatureLength)) {
        return new XZCompressorInputStream(in);
      }
      if (Pack200CompressorInputStream.matches(signature, signatureLength))
        return new Pack200CompressorInputStream(in);
{code}

Ass you can see, the {{XZCompressorInputStream.matches()}} method is a static method.  When the class loader loads this class, it tries to load the import statements at the top of {{XZCompressorInputStream}}:

{code}
import org.apache.commons.compress.compressors.CompressorInputStream;
import org.tukaani.xz.SingleXZInputStream;
import org.tukaani.xz.XZ;
import org.tukaani.xz.XZInputStream;
{code}


And, since these {{org.tukaani.xz}} classes don't exist, a {{NoClassDefFoundError}} exception is thrown.

{code}
java.lang.NoClassDefFoundError: org/tukaani/xz/XZInputStream
at org.apache.commons.compress.compressors.CompressorStreamFactory.createCompressorInputStream(CompressorStreamFactory.java:120)
at org.apache.tika.parser.pkg.ZipContainerDetector.detectCompressorFormat(ZipContainerDetector.java:95)
at org.apache.tika.parser.pkg.ZipContainerDetector.detect(ZipContainerDetector.java:81)
at org.apache.tika.detect.CompositeDetector.detect(CompositeDetector.java:61)
at com.lookout.mimetype.TikaResourceMetadataFactory.createMetadata(TikaResourceMetadataFactory.java:166)
at com.lookout.mimetype.TikaResourceMetadataFactory.createMetadata(TikaResourceMetadataFactory.java:112)
(...)
Caused by: java.lang.ClassNotFoundException: org.tukaani.xz.XZInputStream
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
{code}

The appropriate approach is to see if the classes exist before trying to use them.  If they fail, then XZ is not supported and {{ZipContainerDetector.detect}} will not support XZ files.

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